Keyed joint

ABSTRACT

A keyed joint for enabling relative longitudinal movement to take place between a driving and a driven member under high torque loading conditions includes a shaft member and a coaxial sleeve member. A key is formed on one of the members and a keyway on the other member, the key and keyway each having a face transverse to the circumferential direction and spaced apart circumferentially. A plurality of rollers are located between said faces and the faces are profiled to correspond to the contacting surface of the rollers.

United States Patent 11 1 Montefiore, deceased et al.

1451 Sept. 18, 1973 1 KEYED JOINT [76] Inventors: Herbert RalphMontefiore, deceased, late of Clifton," Station Rd., West llorndon,Essex; by National Westminster Bank, Limited, executor, 41 Lothbury,London, both of England [22] Filed: May 7, 1971 [21] Appl. No.: 141,170

[52] U.S. Cl. 64/23 [51] Int. Cl. Fl6d 3/06 [58] Field of Search 64/23,9, 27.3

[56] References Cited UNITED STATES PATENTS 3,183,684 5/1965 Zeidler64/23 3,494,148 2/l970 Young .1 64/23 3,248,900 5/1966 Shurts 3,478,541ll/l969 McGill et al 64/23.!

Primary Examiner-Edward G. Favors Attorney-Axel A. Hofgren et al.

[57] ABSTRACT A keyed joint for enabling relative longitudinal movementto take place between a driving and a driven member under high torqueloading conditions includes a shaft member and a coaxial sleeve member.A key is formed on one of the members and a keyway on the other member,the key and keyway each having a face transverse to the circumferentialdirection and spaced apart circumferentially. A plurality of rollers arelocated between said faces and the faces are profiled to correspond tothe contacting surface of the rollers.

4 Claims, 4 Drawing Figures Patented Sept. 18, 1973 2 Sheets-Sheet 1Patented Sept. 18, 1973 3,759,065

2 Sheets-Sheet 2 V I 17: 2k:

I 1) |7a 4 I A119 20 v FIG. 4.

KEYED JOINT V .This invention relates to a keyed joint including a shaftand coaxial sleeve for transmittingtorque and providing for relative.longitudinal movement between the shaft and sleeve.

Keyed shaft and sleeve joints have been proposed in which the shaft andsleeve are slidable relatively longitudinally to allow adjustment in thespacing between a driving and a driven member. Such joints, which mayincludesplined shafts, often have a high resistance to relative slidingmovement under high torque loading.

An object of the invention is to provide a keyed joint in which theresistance to relative longitudinal move? ment between the shaft andsleeve under torque loading is reduced.

According to the invention a keyed joint, including a shaft member and acoaxial sleeve member arranged for relative longitudinal movement andkeyed to prevent relative rotation, comprises at least two sets of keyson one of the members and corresponding sets of keyways on the other ofthe members, thekeys and keyways each having a face transverse to thecircumferential direction, the faces being spacedapart circumferentiallyand locating a plurality of cylindrical rollers between them, said facesbeing profiled to correspond to the contacting surface of the rollers,which have their axes of rotation extending radially of the shaftandsleeve members. i

Preferably the keys are formed on the shaft member and the keyways areformed on the sleeve member.

Conveniently each key and keyway together provide two pairs of saidspaced apart transverse faces, and a plurality of rollers are locatedbetween the faces of each pair. -In this way torque can be applied tothe joint in either direction of rotation and, whatever the direction ofrotation, relative longitudinal movement of the shaft and sleeve membersis obtained by a rolling action of the rollers. I

When torque is to be applied to the joint in one direction only, onepair of said spaced apart transverse faces is provided on each key andkeyway, a further pair of faces transverse to the circumferentialdirection being provided on each key and keyway, and said further pairbeing located closely adjacent one another.

Further features of the invention appear from the fol.- lowingdescription of an embodiment of the invention given by way of exampleonly and with reference to the drawings, in which:

FIG. 1 is a side elevation of a splined shaft;

FIG. 2 is a section on the line 2?-2 in FIG. 1;

FIG. 3 is an end elevation .of a sleeve, and

FIG. 4 is a sectional elevation on the line 4-4 in FIG. 3.

Referring to the drawings and firstly to FIGS. 1 and 2 the shaft hasfour keys or splines to regularly spaced circumferentially about theperiphery of the shaft. Each spline '10 has a part cylindrical surface11 bounded by two faces 12 and 13 extending parallel to the axis of theshaft and transverse to the circumferentialdirection of the shaft. Thefaces 12 and l3areflat, and imaginary lines parallel to the facessubtenda small acute angle to radial lines from the axis of the shaft. A partcylindrical surface 14 forms the periphery of the shaft betweenadjacentsplines.

When the vshaft of FIGS. 1 and 2 is assembled with the sleeve of FIGS. 3and 4 to form a joint, cylindrical rollers 15, shown in FIGS. 1 and 2,are located in contact with the faces 12 of the splines 10. The rollers15 have their axes arranged in alignment with radii from the axis of theshaft and the length of the. rollers in their axial direction is equalto the depth of the splines.'The surfaces 12 of the splines contacted bythe rollers are arranged ,parallel to the sides of the'rollers so thatthe rollers each have line contact along the whole of their length withthe associated surface 12. Several rollers are located spaced apartalong and in contact with each of the surfaces 12, the number of rollersprovided being dependent on the length of the sleeve and on the torqueloading of the joint. It will be appreciated that the more rollers thatare provided the lower the load on each roller.

Referring now to FIGS. 3 and 4 which show a cylindrical sleeve 17arranged to fit onto the shaft shown in FIGS. 1 and 2. The sleeve 17 hasinternally projecting ribs 17a defining keyways 18 for the keys forsplines 10 and each keyway 18 has a part-cylindrical surface 19 with aradius of curvature corresponding to that of the spline surface 11. Thesurface 19 is bounded by two faces 20 and 21 of two adjacent ribs 17acorresponding to the faces 12 and 13 on the splines 10 and of similardisposition to the surfaces 12 and 13. The rollers 15 contact the faces20 so that the rollers have line contact along their whole length withthe faces 20. The depth of the keyways 18 is the same as the depth ofthe splines Lubrication of the splines andkeyways and sealing of thejoint against the ingress of dirt and moisture may be obtained by theprovision of an oiled felt pad (not shown) located around the shaft andshaped to fit over the splines. I

The sleeve has four apertures 22 at each end for the location ofretaining pins (not'shown) for holding the rollers 15 in place betweenthe ends of the sleeves; The retaining pins may be held in place by aband (not shown) encircling the sleeve or the ends of the apertures 22may be upset for the same purpose.

The shaft has a diametral bore 23 at its free end for locating aretaining pin (not shown) by which the sleeve is retained on the shaft.

- It will be appreciated that the arrangement described with referenceto the drawings is suitable as a unidirectional joint, i.e., torque isnonnally transmitted through the joint in one direction only theanti-clockwise direction as seen in FIGS. 2 and 3. ,When torque loadingof the joint in this direction is taking place relativelongitudinal-movement of the shaft and sleeve can take place withoutundue resistance, due to the rolling action of the rollers along theassociated transverse faces of the splines and keyways. During torqueloading the rollers are subjected to largely compressive forces.

The splines and keyways instead of being parallel to the axis of theshaft may be inclined to said axis.

The joint described with reference to the drawing may be adapted toserve as a bi-directional joint by the provision of rollers between thefaces 13 and 21, as well as between the faces 12 and 20. In thisarrangement the faces 13 and 21 are spaced circumferentia'lly from oneanother when the shaft and sleeve are assembled to locate the rollers,and relative movement between the shaftand sleeveis obtained in bothdirectionsof rotation in a similar manner.

Preferably the combined length of each row of rollers is half themaximum relative movement between the shaft and the sleeve. At theextremes of said movement 7 the rollers will come up against theretaining pins and will momentarily contact the pins. The rollers then.reposition themselves until they are again'spaced apart.

The outer diameter of the shaft is as large as can be accommodated inthe desired housing so as to minimise torsional deflection. The sleeveis designed so as to match as near as practicable the torsionaldeflection of the shaft, thereby evening out the load distributionbetween the rollers.

The joint described is relatively cheap to manufacture and has arelatively long life. Moreover the joint allows relative movementbetween the shaft and sleeve to take place relatively easily due to thelow resistance to this movement even when the joint is under hightorsional load.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. In a keyed joint which includes a shaft member and a coaxial sleevemember arranged for relative longitudinal movement and keyed to preventrelative rotation so as to transmit rotary driving force from one memberto the other, the improvement comprising:

two sets of keys on one of the members;

corresponding sets of keyways on the other of the members, the keys andkeyways each having faces transverse to the circumference of themembers, with pairs of the faces being spaced apart circumferentially;

and a plurality of rigid cylindrical rollers between each cooperatingpair of faces with their axes of rotation effectively on radii of themembers;

each set of keys having two keys located on opposite sides of the axisof rotation of the members from one another, and the keys and keyways ofone set being angularly displaced substantially 90 from the keys andkeyways of the other set.

2. A keyed joint according to claim 1 wherein the keys are formed on theshaft member and the keyways are formed on the sleeve member.

3. A keyed joint according to claim I wherein one pair of said spacedapart transverse faces is provided on each key and co-operating keyway,a further pair of faces transverse to the circumferential directionbeing provided on each key and cooperating keyway,and said further pairbeing located closely adjacent one another. a

4. In a keyed joint which includes a shaft member and a coaxial sleevemember arranged for relative longitudinal movement and keyed to preventrelative rotation so as to transmit rotary driving force from one memberto the other, the improvement comprising:

a set of keys on one of the members, each of said keys having facestransverse to the circumference of the members;

a corresponding set of keyways on the other of the members, each of saidkeyways receiving one of the keys and having faces which are parallel tothose of said one of the keys, and cooperating pairs of said parallelfaces being spaced apart;

and a plurality of rigid, cylindrical rollers between each cooperatingpair of parallel faces, the axes or rotation of said rollers beingparallel to said cooperating pairs of parallel faces, so the rollersmake line contact with said faces, and said axes of rotation beingeffectively on radii of the members,

said set of keys and corresponding set of keyways including a single keyand keyway positioned on one side of a plane through the axis ofrotation of the members and substantially from said plane, and at leastone key and keyway on the other side of said plane, and said keys andkeyways being angulariy substantially equidistant from one another.

1 l' l i jg gg UNITED STATES PATENT OFFICE I n CERTIFICATE OF-CORRECTIONPatent No. D d September 18, Herbert Ralph Montefiore, Deceased, by

'- InVe National Westminster Bank Limited. Enqland 'Itis certified thaterror appears in the 'ahove-identified patent and that said LettersPatent are hereby corrected as shown below:

Page 1, insert the following in the line following the name of theinventor and applicant:

[73] Assignee: Rotary Hoes Limited,

1 a British company, West Horndon,

Essex, England.

Signed and sealed this 16th day of July 1974.

- I (SEAL) Attest:

MCCOY M. GIBSON, JR. 0. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. In a keyed joint which includes a shaft member and a coaxial sleevemember arranged for relative longitudinal movement and keyed to preventrelative rotation so as to transmit rotary driving force from one memberto the other, the improvement comprising: two sets of keys on one of themembers; corresponding sets of keyways on the other of the members, thekeys and keyways each having faces transverse to the circumference ofthe members, with pairs of the faces being spaced apartcircumferentially; and a plurality of rigid cylindrical rollers betweeneach cooperating pair of faces with their axes of rotation effectivelyon radii of the members; each set of keys having two keys located onopposite sides of the axis of rotation of the members from one another,and the keys and keyways of one set being angularly displacedsubstantially 90* from the keys and keyways of the other set.
 2. A keyedjoint according to claim 1 wherein the keys are formed on the shaftmember and the keyways are formed on the sleeve member.
 3. A keyed jointaccording to claim 1 wherein one pair of said spaced apart transversefaces is provided on each key and co-operating keyway, a further pair offaces transverse to the circumferential direction being provided on eachkey and cooperating keyway, and said further pair being located closelyadjacent one another.
 4. In a keyed joint which includes a shaft memberand a coaxial sleeve member arranged for relative longitudinal movementand keyed to prevent relative rotation so as to transmit rotary drivingforce from one member to the other, the improvement comprising: a set ofkeys on one of the members, each of said keys having faces transverse tothe circumference of the members; a corresponding set of keyways on theother of the members, each of said keyways receiving one of the keys andhaving faces which are parallel to those of said one of the keys, andcooperating pairs of said parallel faces being spaced apart; and aplurality of rigid, cylindrical rollers between each cooperating pair ofparallel faces, the axes or rotation of said rollers being parallel tosaid cooperating pairs of parallel faces, so the rollers make linecontact with said faces, and said axes of rotation being effectively onradii of the members, said set of keys and corresponding set of keywaysincluding a single key and keyway positioned on one side of a planethrough the axis of rotation of the members and substantially 90* fromsaid plane, and at least one key and keyway on the other side of saidplane, and said keys and keyways being angularly substantiallyequidistant from one another.